With the improvement of living standard and the development of refrigerator-related technologies, refrigerators provided with sections for keeping fresh at 0° C. and soft freezing at −7° C., or refrigerators featuring adjustable sections of variable temperature, have become dominant products of superior refrigerators in China.
The main technology employed in the existing refrigerators of this kind is that a parallel connected assembly, constituted by a bistable two-position three-way solenoid valve and a bistable single-way valve, is used such that the number of the temperature section can be increased, as shown in FIG. 1. The functions achieved by such a parallel connected assembly constituted by a bistable two-position three-way solenoid valve and a bistable single-way valve are that: an inlet, three outlets and then four combined functional modes can be obtained.
The refrigerating system for refrigerators shown in FIG. 1 additionally comprises a variable temperature section evaporator (a refrigerator with a section for keeping fresh at 0° C. and soft freezing at −7° C. may be also provided), the refrigerating system employs a bistable solenoid valve and a bistable single-way valve connected in parallel and has the following four refrigerating operation modes:
Mode No. 1, the mode of refrigeration cycle through single circuit, is as follows:
compressor 1→condenser 2→drier-filter 3→solenoid valve 4→straight solenoid valve 5→refrigerator-applied capillary tube 8→refrigerator-applied evaporator 9→freezer-applied evaporator 11→compressor (suction);
Mode No. 2, the mode of refrigeration simultaneously through two circuits, is as follows:
compressor 1→condenser 2→drier-filter 3→solenoid valve 4→straight solenoid valve 5→refrigerator-applied capillary tube 8→refrigerator-applied evaporator 9→freezer-applied evaporator 11→compressor (suction);
compressor 1→condenser 2→drier-filter 3→solenoid valve 4→variable temperature capillary tube 7→variable temperature evaporator 10→freezer-applied evaporator 11→compressor (suction);
Mode No. 3, the mode of refrigeration simultaneously through two circuits, is as follows:
compressor 1→condenser 2→drier-filter 3→solenoid valve 4→variable temperature capillary tube 7→variable temperature evaporator 10→freezer-applied evaporator 11→compressor (suction);
compressor 1→condenser 2→drier-filter 3→solenoid valve 4→straight solenoid valve 5→freezer-applied capillary tube 6→freezer-applied evaporator 11→compressor (suction);
Mode No. 4, the mode of refrigeration through single circuit, is as follows:
compressor 1→condenser 2→drier-filter 3→solenoid valve 4→straight solenoid valve 5→freezer-applied capillary tube 6→freezer-applied evaporator 11→compressor (suction).
The afore-mentioned parallel connected assembly including two bistable two-position three-way solenoid valves, when is used, has the following disadvantages:
The assembly is complicated in structure and occupies big space in a refrigerator; The action noise generated by the bistable solenoid valve is big;
The action frequency will be increased when employing two solenoid valves, thus the noise becomes a key factor which deteriorates the quality of a refrigerator;
The bistable solenoid valves are driven by half-wave pulse similar to alternating current, thus being vulnerable to interferences and making it necessary to add sustain pulses periodically so as to avoid errors, yet applying periodical pulses further deteriorates the quality of a refrigerator in respect of noise.
A shorted circuit exists when two circuits are communicated through at the same time in refrigeration mode No. 3, to solve this problem, it is necessary to employ three single-way solenoid valves connected in parallel in some systems in order to meet functional requirements thereof.